On Friday I gave a presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars. If you missed it, you can still…: Can you compare the use of subqueries/multiple joins vs. multiple queries (e.g. temp tables)? For performance, it’s hard to make… to force MySQL to scan the `title` table first, grouping by kind_id in index order. This made the first table in the…
Post: Choosing a MySQL HA Solution - Post-Webinar Q&A
June 7, 2013 By Leave a Comment
… which will allow you to stripe a TCP connection over multiple ports, and with a two-NIC bonded pair you’ll… the MySQL manual. You can configure the slave to only replicate a specific database, a set of databases, or specific tables; you…: Incorrect information in file: ‘./mysql/servers.frm’ ERROR: 1033 Incorrect information in file: ‘./mysql/servers.frm’ Running mysql_install_db under strace, I…
Post: Follow these basics when migrating to Percona XtraDB Cluster for MySQL
May 1, 2013 By 10 Comments
Galera/Percona XtraDB Cluster (PXC) for MySQL is a hot thing right now and some users jump … May Lead to Inconsistencies and May Not Even Work! MyISAM tables are supported within Percona XtraDB Cluster, however, MyISAM has only… you are planning to write on multiple nodes. Have PRIMARY KEYS If you still have tables without PRIMARY KEYs, then its time…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
… MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL replication…mean you can’t modify data on multiple cluster nodes simultaneously. You can. It … maintained in separate tables and there also exists a users_groups table to define the relationship…
Post: Why MySQL Performance at Low Concurrency is Important
March 27, 2013 By 8 Comments
… important baseline that offers the best response times (MySQL server does not use multiple threads to execute query in parallel at this… jobs are written to be single-threaded. MySQL replication is single-thread too, and MySQL 5.6 brings some abilities of parallel… of benchmarks, Mark Callaghan published an example where 8 sysbench tables are used which means the lowest concurrency you can run…
Post: Innodb Table Locks
July 31, 2012 By 4 Comments
… IX is rather lose – I can have multiple update queries running on the table each locking it in IX mode, which will… “converts” table lock to “no lock” hence eliminating conflicts on MySQL level table locks for most queries. Summary: MySQL Table level locks and Innodb Table Level… increment table level lock (mostly with MySQL 5.0 and older MySQL versions). MySQL level locks are entirely different story. Explicitly locking tables on MySQL level…
Post: Wow. My 6 year old MySQL Bug is finally fixed in MySQL 5.6
August 30, 2012 By 2 Comments
… I reported in Early 2006 (while still being with MySQL) and running MySQL 4.1 I honestly thought this issue was fixed… really need is with 2147483647) mysql> explain select count(*) from trunc where i=4147483647; +—-+————-+——-+——+—————+——+———+——-+——-+————————–+ | id | select_type | table | type | possible_keys | key… application which would use multiple table and the column type was inconsistent between them… so inserts into one table would happen with correct…
Post: Sysbench with support of multi-tables workload
April 29, 2011 By 4 Comments
… just pushed to sysbench support for workload against multiple tables ( traditionally it used only single table). It is available from launchpad source tree…=25 prepare run: ./sysbench –test=tests/db/oltp.lua –oltp-tables-count=25 –num-threads=5 run oltp.lua should understand… may use ./sysbench –test=tests/db/parallel_prepare.lua –oltp-tables-count=64 –num-threads=8 run ( please note that oltp…
Post: Using Multiple Key Caches for MyISAM Scalability
November 26, 2008 By 8 Comments
… using Multiple Tables to solve Table Locks problem you can also use multiple Key …TABLES table: mysql> select table_schema,table_name,index_length from information_schema.tables where table_schema=’test’ and table_name in (‘a’,'b’); +————–+————+————–+ | table_schema | table…
Post: Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2
May 3, 2011 By 13 Comments
… thread and in MySQL 5.6.2 one can have multiple dedicated purge threads. Percona Server 5.1 supports multiple purge threads too…_pct=80 innodb_file_format=barracuda innodb_file_per_table max_connections=2000 table_cache=2000 Percona Server 5.1 Results For… setting–multiple purge thread implementation at the moment seems to be the one in Percona Server 5.1. MySQL 5.6.2 multiple…
